Shallow-level muonium centre in CdS

• Autor(a) principal: Gil, J. M.
• Data de Publicação: 2000
• Outros Autores: Alberto, H. V., Vilão, R. C., Duarte, J. Piroto, Mendes, P. J., Campos, N. Ayres de, Weidinger, A., Krauser, J., Niedermayer, Ch., Cox, S. F. J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/4528; https://doi.org/10.1016/S0921-4526(00)00257-X
• topic: II-VI semiconductors; Hydrogen-like defects; Muonium states

A new type of muonium defect centre has been observed in undoped CdS at low temperatures (T<20 K). The hyperfine parameters are A[short parallel]=335 (7) kHz and A[perpendicular]=199 (6) kHz (approximately 10-4 of the vacuum value) with the symmetry axis along the Cd-S bond direction. The disappearance of the centre at around 20 K is in agreement with the binding energy of a shallow centre. The extremely weak hyperfine interaction implies that the electron is only weakly bound to the muon and is distributed over a large complex of atoms in the neighborhood of the muon resembling the dilated hydrogen-like wave functions of shallow centres in a dielectric medium. Comparing the hyperfine interaction with that of free muonium, a Bohr radius of ad=26a0=1.4 nm is calculated for this defect, with a0 being the Bohr radius for the free muonium.